Device for mounting, dismounting and transporting curved objects that are easy to bend and have hanging up edges

ABSTRACT

A device for mounting, removing and transporting an easily bendable device, such as a printing plate, to and from a plate cylinder includes a printing plate preparation device which supports the plate, and a cross arm with a plate gripper and pressing assembly. A gripper portion of the plate gripper and pressing assembly acts on the plate and is movable toward and away from a suspension strip of a cylinder. The plate gripper and pressing assembly can be moved to a parked position where it is out of the way and is shielded from contaminants.

FIELD OF THE INVENTION

The present invention relates to a device for mounting, removing andtransporting of easily bendable curved objects with suspension edges,preferably printing plates, on and from a cylinder of a rotary printingpress.

DESCRIPTION OF THE PRIOR ART

DE 28 04 970 A1 describes a device for mounting and removing printingplates in a rotary printing press.

In this case a suction element performs a linear movement between adelivery roller and a plate cylinder and in this way transports theprinting plate.

This suction element is fastened by means of cylinders on a carriagedriven by a chain. By means of this cylinder, the suction element canperform a tilting movement at right angles in respect to the carriagemovement for lifting and lowering the printing plate. For assembly, thesuction element fixes a beveled front edge of the printing plate inplace by switching on the suction effect. The suction element togetherwith the plate is lifted by means of the cylinder and moved in thedirection toward the plate cylinder by the carriage with the chaindrive. A positioning table is located between the delivery roller andthe plate cylinder, on which the printing plate is placed andpositioned. Thereafter, the suction element again picks up the printingplate and transports it to a groove of the plate cylinder. The bevelededge of the printing plate is inserted into this groove of the platecylinder by lowering the suction element.

After the suction effect has been turned off, the plate cylinder turnstogether with the printing plate which is simultaneously wound off thedelivery roller. Once the printing plate is almost completely wound offthe delivery roller, the suction element grips a rear of the printingplate and guides it into a further groove of the plate cylinder.

It is disadvantageous in connection with this prior art device that itis necessary to deposit and position the printing plate on a positioningtable which is located between the delivery cylinder and the platecylinder. It is possible for tolerances, for example because of play inthe carriage guidance, to occur during the transport of the printingplate from the positioning table to the cylinder and during thesuspension process of the printing plate in the cylinder, which cause anerroneous axial position of the printing plate on the cylinder.

US 47 27 807 A describes a device for mounting and removing printingplates in a rotary printing press. In this case, a manipulation devicewhich picks up the printing plates is moved by a robot between apreparation device and a plate cylinder. Four suction grippers, by meansof which the printing plate is held, are rigidly disposed on themanipulation device.

For assembly, the printing plate is moved from the preparation device tothe plate cylinder by multi-axial movements of the robot and issuspended with a beveled edge in a clamping channel of the cylinder.

The axial positioning of the printing plate takes place via a drivewhich is regulated by means of force sensors. Subsequently, fourpressure rollers are applied by pivoting the manipulation device. Theprinting plate is placed on the plate cylinder by rotating the platecylinder and a further end is inserted into the channel.

It is disadvantageous with this device that the manipulation unit mustbe movable and pivotable in several directions in the radial plane ofthe plate cylinder and that complicated drives and controls are requiredfor this. It is furthermore not possible to transport and mount orremove several printing plates per cylinder simultaneously.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a device formounting, removing and transporting easily bendable, curved objects withsuspension edges, preferably printing plates, whose respective legs forman angle of less than 90° and which have no recesses for register pins,on and from a cylinder which, in a parking position, makes possible anoperation and maintenance without hindrance and also makes possible freeaccess to the print units as well.

This object is attained in accordance with the invention by means of aplate preparation device which is situated near the plate cylinder. Across arm carries at least one gripper and pressing device and ismovable in a transport plane which is generally parallel to a tangent ofthe plate cylinder. A gripper unit of the gripping and pressing deviceis equipped with suction strips which act on the printing side of theprinting plate. This gripper unit is movable toward and away from asuspension strip of the cylinder and is movable parallel to an axis ofrotation of the cylinder along the suspension edge of the cylinder. Thedevice can be moved to a parked position close to the cylinder where itis out of the way and provides free access to the print units.

In a particularly advantageous manner, a gripper and pressing deviceneeds only travel over a short distance in order to get into a parkedposition or into the work position, which is very important for shortplate changing times. If the gripper and pressing device is in theparked position, good accessibility to the cylinder and an associatedinking unit is assured. Thus, a manual plate change is also possible atany time without the device in accordance with the invention hamperingsuch a manual plate change.

In the parked position the gripper and pressing device is enclosed by aprotector and in this way is protected from dirt and ink fog, whichincreases operational dependability and minimized the maintenanceeffort.

BRIEF DESCRIPTION OF THE DRAWINGS

The device in accordance with the invention is represented in thedrawings and will be described in more detail in what follows.

Shown are in:

FIG. 1, a schematic representation of the device in accordance with thepresent invention in a top view,

FIG. 2, a schematic representation of a gripper and pressing device ofthe device in accordance with the present invention in FIG. 1,

FIGS. 3 to 11, schematic lateral views of the device in accordance withthe present invention with associated cylinder and preparation devicesin various operating positions, and

FIG. 12, a schematic section through a closure of the cylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a cylinder 1 of a rotary printing press with easilybendable curved objects 2, preferably printing plates 2.

Respectively beveled front and rear suspension edges 3, 4 are disposedon opposite ends of every easily bendable curved object 2 as may be seenin FIG. 4, and whose respective legs 6, 7 form an opening angle alpha ofless than 90°. These beveled suspension edges 3, 4 are embodied to bedimensionally stable, i.e. these beveled suspension edges 3, 4 are notbent open when clamping the objects 2 on the cylinder 1. This object 2designed in this manner can also consist of rubber blankets providedwith beveled suspension edges 3, 4.

These dimensionally stable beveled suspension edges 3, 4 of the rubberblankets can be beveled edges of a metal plate, on which the rubberblanket is fastened by adhesion between the materials, for example gluedor vulcanized. It is also possible for particularly the textile insertsof the rubber blanket to be made of CFK (carbon fiber reinforcedplastic) or GFK (glass-fiber reinforced plastic) and the beveledsuspension edges 3, 4 to be formed from this. For simplification, thedescribed object is hereinafter called printing plate 2.

An inking unit protector 11, which is located close to the cylinder asseen in FIG. 3, fixed in the frame, and which is embodied as a firstprinting plate preparation device 12, is associated with the cylinder 1of the rotary printing press, which is seated in two side frames 8, 9that are shown in FIG. 1.

This printing plate preparation device 12 has an upper wall 13 and alower wall 14, located opposite the upper, which together form a chute16. A suspension strip 19 of nose-shaped cross section, which extendsover the width of the cylinder 1 and extends parallel with an axis ofrotation 18 of the cylinder 1, is disposed at an end 17, close to theplate cylinder, of the upper wall 13 of the printing plate preparationdevice 12. The end 17, close to the plate cylinder, of the upper wall 13is designed approximately parallel with a tangent 21, which isdetermined by a cylinder surface 22 of the cylinder 1 and the suspensionstrip 19 of the printing plate preparation device 12.

It is possible, as in the instant example, for a second printing platepreparation device 23 to be disposed besides the first printing platepreparation device 12, whose end 24 close to the plate cylinder is alsoprovided with a suspension strip 26 of nose-shaped cross section andwhich is embodied approximately parallel with the tangent 21 determinedby the cylinder surface 22 of the cylinder 1 and the suspension strip 19of the first printing plate preparation device 12.

Respectively a right and left linear drive 27, 28 as depicted in FIG. 3,is fastened in the side frames 8, 9 above and parallel with this tangent21, which for example respectively consists of thread spindles 29, 31,which are rotatably seated in brackets 32, 33, 34, 36 fixed on theframe. It is possible to employ other known linear drives 27, 28, forexample belt or chain drives, toothed rack drives, hydraulic orpneumatic servo cylinders or linear motors, in the same manner. Asynchronous rotating movement of the threaded spindles 29, 31 isgenerated by means of a belt 37, for example a toothed belt, whichmechanically synchronizes the right and left threaded spindles 29, 31.This synchronization can take place mechanically also by means of chainor drive shafts or electronically via two separate drives 38 of thelinear drives 27, 28. The two threaded spindles 29, 31 move a cross arm39 seen in FIGS. 1 and 2, and which is parallel with the axis ofrotation 18 of the cylinder 1, in a transport plane 41 which is locatedabove and approximately parallel with the tangent 21 determined by thecylinder surface 22 of the cylinder 1 and the suspension strip 19 of theprinting plate preparation device 12. Threaded nuts 42 are respectivelydisposed at the two ends of this cross arm 39, so that the cross arm 39is in an operative connection at right angles with the threaded spindles29, 31. At least one gripper and pressing device 43 is fastened alongthis cross arm 39, in the represented example shown in FIG. 1 there areprovided four gripper and pressing devices 43.

An independently operable gripper and pressing device 43 is associatedwith each individual printing plate 2 associated with an axial cylindersection. However, in the same way it is also possible by means of anadditional linear drive, through which a single gripper and pressingdevice 43 performs an axial movement along the cross arm 39, to changeseveral printing plates 2 disposed along the cylinder 1 with only asingle gripper and pressing device 43.

The elements of a gripper and pressing device 43 are represented in FIG.2:

A gripper and pressing device 43 consists of at least one gripper unit44 and at least one pressing roller 46. This gripper unit 44 and thepressing rollers 46 are individually displaceable by means ofpositioning devices independently of each other in respect to thecylinder 1 in the radial direction "D", and the gripper unit 44additionally also in the axial direction "C".

In the instant example, the gripper and pressing device 43 isconstructed approximately symmetrical in respect to the center line ofthe printing plate 2 extending in the direction of the cylindercircumference:

In each gripper and pressing device 43, a gripper unit 44 is embodied,for example, in the form of two suction strips 47, which aredisplaceable, secure against relative twisting, perpendicularly inrespect to a guide strip 48 opposite the tangential direction "B" of thecylinder 1, and are pushed in the direction "B" against a stop 51 bypressure springs 49.

These guide strips 48 are fastened on a further guide strip 52 and aredisplaceable opposite the direction "C" by means of a pneumatic cylinder53. A pneumatic cylinder 54 causes a position change of the guide strip52 with the suction strips 47 along the direction "D". A pressing roller46 is respectively located next to the suction strips 47, which can beplaced against the printing plate 2 opposite the direction "D" via apneumatic cylinder 56.

In the instant example, as seen in FIG. 3, four closures 57, 58, 59, 61are disposed in the cylinder 1 in the axial direction, extendingparallel with the axis of rotation 18 of the cylinder 1. The length ofthe closures 57, 58, 59, 61 respectively is approximately half acylinder length. These closures 57, 58, 59, 61 are again divided in thewidth of the plate (i.e. respectively two printing plates 2 are providedper closure 57, 58, 59, 60), and can be independently actuated bothwithin this division and also in respect to each other. The closures 57,58 are offset in respect to each other by approximately 90° in thecircumferential direction of the cylinder 1. A closure 59, 61 isrespectively associated with each opposite closure 57, 58.

The mode of functioning of the closures 57, 58, 59, 61 will be explainedin more detail below by reference to the closure 57 which is depicted indetail in FIG. 12.

The closure 57 is disposed in a cylinder hole or channel 62 extendingparallel with the axis of rotation 18. Respectively one front and onerear suspension strip 63, 64 of a nose-shaped cross section is disposedon the cylinder 1 and delimits the cylinder hole or channel 62 beneaththe cylinder surface 22. The closure 57 has a right and a left clampingflap 66, 67. Each one of these clamping flaps 66, 67 extendsapproximately over the width of the plate in the axial direction alongthe axis of rotation 18 of the cylinder 1. The cross section of bothclamping flaps 66, 67 is embodied circular arc-shaped on its lower endas a seating place, from which a lever 69 projects, which terminates ina hook-shaped nose 71. In the opened state of the clamping flaps 66, 67,their noses 71 are located below the cylinder surface 22, and theirsides 72 facing the suspension strips 63, 64 of the cylinder 1 arebeveled in correspondence with the suspension strips 63, 64 of thecylinder 1, so that in the opened state the clamping flaps 66, 67 areessentially covered by the suspension strips 63, 64.

In the clamped state of the clamping strip 67, a side 73 of the nose 71of the clamping flap 66 facing the beveled suspension edge 4 of thepressure plate 2 extends approximately parallel with the beveledsuspension edge 3 of the printing plate 2. The circular arc-shaped end68 is respectively seated pivotably in a circular arc-shaped recess 74of the cylinder hole or channel 62, which extends parallel with the axisof rotation 18. Under the action of springs, the clamping flap 67performs a pivot movement in the direction towards the rear beveledsuspension edge 4 of the printing plate 2 which is to be clamped. In theinstant example, the circular arc-shaped end 68 of the clamping flap 67is provided with a bore 77, through which a rod-shaped torsion spring(torsion bar) 76 extends. On one of its ends, this torsion bar 76 isrigidly connected with the cylinder 1, while its second end is fixed inplace on one end of the clamping flap 67.

It is possible, as in the described example, for a further clamping flap66 to be disposed axially symmetrical in respect to a center line 78opposite this clamping flap 67 (so that it is also possible to operatein the opposite direction of rotation of the cylinder 1), or only afiller could be inserted. A device generating a force acting on thelever 69 of the two clamping flaps 66, 67 is disposed between these twoclamping flaps 66, 67 or the filler. In the instant example, anon-elastic, inflatable hose 79 is disposed between the two clampingflaps.

With the clamping flaps 66, 67 closed, i.e. with a clamped printingplate 2, this hose 79 is compressed flat between the clamping flaps 66,67. If this hose 79 is charged, for example with compressed air, bymeans of the change of the shape of the hose 79 it generates a forceacting opposite the torsion bar 76 on the lever 69 of the clamping flaps66, 67 and they therefore pivot in the direction of the insertion strips63, 64 of the cylinder 1, because of which the closure 57 opens and thebeveled insertion edge 4 of the printing plate 2 comes free.

The changing process of a printing plate 2 will be explained in moredetail by reference to FIG. 2 to FIG. 11:

The cross arm 39 with the gripper and pressing device 43 is moved from aparked position into its unclamping position by the two linear drives27, 28, while the cylinder 1 rotates into its unclamping position. Theunclamping position of the cross arm 39 is determined in that the crossarm 39 is located approximately on or close to a perpendicular line 81,drawn from the axis of rotation 18 of the cylinder 1 to the threadedspindles 29, 31 of the linear units 27, 28. Thus, in this unclampingposition the pressing rollers 46, which later are placed against theprinting plate 2, determine a loosening point 82 of the printing platefrom the cylinder 1 in such a way that a tangent 83 applied in theloosening point 82, i.e. the printing plate 2 as seen in FIG. 4,terminates in the chute 16 of the printing plate preparation device 12.The unclamping position of the cylinder 1 as seen in FIG. 3 isdetermined in that the described perpendicular line 81 forms an angle ofapproximately 10° opposite the production direction with a connectionline formed by a center line 78 of the closure 57 and the axis ofrotation 18. The parked position of the cross arm 39 with the gripperand pressing device 43 is located in the transport plane 41, viewed inthe plate feed direction A, at least sufficiently far behind theperpendicular line 81 extending from the axis of rotation 18 of thecylinder 1 to the threaded spindles 29, 31, that manual printing platechanges, for example, can be performed, for example 100 mm to 200 mm.Thus the parked position is located outside of the plate transport path.The two pressing rollers 46 are pressed on the loosening point 82 of theprinting plate 2 by the pneumatic cylinders 46 in order to preventslippage of the printing plate 2 on the cylinder 1 as seen in FIG. 4.Thereafter a closure 57 of the cylinder 1 opens and the cylinder startsto turn opposite the production direction "P" (FIG. 3). Because of theinherent stiffness of the printing plate 2, it springs out of theclosure 57 which, following a rotating movement of the cylinder 1 ofapproximately 10°, closes again.

During the rotating movement of the cylinder 1, the printing plate 2 isguided on the cylinder 1 in a frictionally connected manner because ofthe force effect of the pressing rollers 46, and in this way theprinting plate end reaches the chute 16 of the inking unit protector 11.The cylinder 1 stops as seen in FIG. 4, approximately 10° to 30° beforethe front suspension strip 63 of the cylinder 1 reaches the pressingrollers 46, and the printing plate 2 is fixed in place in the chute 16by means of a not further shown device. Thereafter, the cylinder 1 turnsat least far enough against the production direction "P", because ofwhich the printing plate 2 is displaced on the cylinder 1, until theprinting plate 2 springs out of the suspension strip 63 because of itsinherent torsion as seen in FIG. 5. The pressing rollers 46 are drawnback from the cylinder 1 by means of the pneumatic cylinders 56.

The printing plate is subsequently removed from the cylinder 1 by meansof a device, not shown, in the chute 16 and is completely transportedinto the chute 16.

For clamping a fresh printing plate 84 as seen in FIG. 6, the cylinder 1turns into its initial position which is determined in that the centerline 78 of the closure 57 is approximately congruent with theperpendicular line 81 extending perpendicularly with the movementdirection of the linear drives 27, 28 from the axis of rotation 18. Thecross arm 39 is brought into a position for receiving the fresh printingplate 84 by means of the two linear drives 27, 28, i.e. the suctionstrips 47 are located in the area of the end close to the plate cylinderof the printing plate preparation device 12. The gripper unit 44 isdisplaced opposite the direction "C" by charging the pneumatic cylinder53 with air.

The printing plate 84 to be newly applied had been placed pre-positionedon the upper wall 13 and on the suspension strip 19 of the printingplate preparation device 12.

The suction strips 47 are lowered to the level of the printing plate 84by bleeding the air from the pneumatic cylinders 54 and are charged withsuction air as seen in FIG. 6. By means of this, the printing plate 84is fixed with its printing side on the gripper and pressing device 43.The cross arm 39 is now moved in the direction toward the cylinder 1 andafter a distance of approximately 10 mm has been traveled, the suctionstrips 47 with the printing plate 84 are lifted by means of thepneumatic cylinders 54.

The cross arm 39 with the gripper and pressing device 43 conveys theprinting plate 2 in the direction toward the front suspension strip 63of the cylinder 1 until the front beveled suspension edge 3 of theprinting plate 84 forms a gap "s" with the suspension strip 63 of thecylinder 1, so that the gripper unit 44 with the suction strips 47 canlower the printing plate 84 by means of the pneumatic cylinder 54 on thecylinder surface 22 all as seen in FIG. 7. This gap "s" is approximately2 mm to 5 mm.

Following the lowering of the printing plate 84, the linear drives 27,28 move the gripper and pressing device 43 opposite the direction "A"until the front beveled suspension edge 3 of the printing plate 84 restsexactly against the suspension strip 63 of the cylinder 1 and thesuction strips 47 pre-stress the printing plate 84 with a defined forceopposite the direction "B". This is shown in FIG. 8.

Subsequently the printing plate 84, which is held by the suction strips47, is positioned axially and parallel with an axis of rotation 18 ofthe cylinder 1 on a respective lateral register stop 86, which is shownin FIG. 12 with a defined force, for example resiliently, by actuatingthe pneumatic cylinder 53, so that the printing plate 84 rests securelyagainst the lateral register stop 86, but is not deformed. The springforce for positioning the printing plate 84 can be generated, forexample, by means of the spring of a single-acting pneumatic cylinder 53or by the air pressure (for example adjustable by means of pressureregulators) of a double-acting pneumatic cylinder. The lateral registerstops 86 are fixed with the cylinder on the suspension strip 63 of thecylinder 1 below the cylinder face 22. In the example shown, a commonlateral register stop 86 is located on the left or right lateral edge ofthe printing plate 84 associated with the respective cylinder section.

The described functioning of the pneumatic cylinder 53 applies in caseof the disposition of the lateral register stop 86 on the left lateraledge, i.e. in the direction C. In case of the disposition of the lateralregister stop 86 on the right lateral edge, the pneumatic cylinder 53must act in the opposite direction.

Afterwards, the two pressing rollers 46 are lowered by means of therespective pneumatic cylinders 56 on the printing plate 84. The suctionair of the suction strips 47 is shut off and the suction strips 47 arelifted in the direction "D" by charging the pneumatic cylinder 54 withsuction air, as may be seen in FIG. 9.

Thereupon the cylinder 1 turns in the production direction "P" until thepressing rollers 46 are located approximately 10° to 20° ahead of therear beveled suspension edge 4 of the printing plate 84, whereupon theclosure 57 opens, as shown in FIG. 10. Subsequently, the cylinder 1turns approximately 5° to 10° in the production direction "P" and theprinting plate 84 is clamped on the cylinder 1 by closing the closure57. The pressing rollers 46 are raised and the cross arm 39 with thegripper and pressing device 43 moves into the parked position. There thepneumatic cylinder 54 is bled and the gripper unit 44 is lowered, asdepicted in FIG. 11. In this parked position, the gripper and pressingdevice 43 is surrounded by a protector 87 which is closed on at leastthree sides and is protected there against dirt and ink.

Alternatively, it is possible to perform a further plate change in thedescribed manner. For this purpose, the second printing platepreparation device 23 is disposed next to the first printing platepreparation device 12, so that the end 24, close to the cylinder, of theprinting plate preparation device 23 is also embodied for positioning asecond, fresh printing plate 88 approximately parallel with the tangent21 of the cylinder surface 22.

Corresponding to the first described removal process, the chute 16 ofthe first preparation device 12 receives a second, used printing plate2.

For mounting the second, fresh printing plate 88 it is placedpre-positioned on the second preparation device 23, and the mountingprocess takes place in a manner equivalent to the first one.

We claim:
 1. A device for mounting, removing and transporting an easilybendable, curved printing plate having front and rear, dimensionallystable beveled suspension edges which are resistant to being bent open,and whose respective legs form an opening angle (alpha) of less than90°, on and from a cylinder of a rotary printing press, which has atleast one suspension strip of a nose-shaped cross section and a closurewhich engages said rear beveled suspension edge of the printing plateand which has pivotable resilient clamping flaps comprising:a gripperand pressing device for a printing plate which is to be removed ormounted, said gripper and pressing device being disposed positionable inand movable to a parked position close to the cylinder; and lineardrives for moving said gripper and pressing device to said parkedposition and wherein said linear drives include threaded spindles, saidparked position being located in an extension of said linear drives in aproduction direction past a disengagement position determined by theintersection of a perpendicular line drawn from an axis of rotation ofthe cylinder with said threaded spindles of said linear drives.
 2. Thedevice in accordance with claim 1, characterized in that said gripperand pressing device is enclosed in said parked position close to thecylinder by a protector which is closed on at least three sides.